1 files changed, 451 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.Gpu/Shader/HashTable/PartitionHashTable.cs b/src/Ryujinx.Graphics.Gpu/Shader/HashTable/PartitionHashTable.cs
new file mode 100644
index 00000000..d7cb3d99
--- /dev/null
+++ b/src/Ryujinx.Graphics.Gpu/Shader/HashTable/PartitionHashTable.cs
@@ -0,0 +1,451 @@
+using System;
+using System.Collections.Generic;
+using System.Numerics;
+
+namespace Ryujinx.Graphics.Gpu.Shader.HashTable
+{
+    /// <summary>
+    /// Partitioned hash table.
+    /// </summary>
+    /// <typeparam name="T">Hash table entry type</typeparam>
+    class PartitionHashTable<T>
+    {
+        /// <summary>
+        /// Hash table entry.
+        /// </summary>
+        private struct Entry
+        {
+            /// <summary>
+            /// Hash <see cref="OwnSize"/> bytes of <see cref="Data"/>.
+            /// </summary>
+            public readonly uint Hash;
+
+            /// <summary>
+            /// If this entry is only a sub-region of <see cref="Data"/>, this indicates the size in bytes
+            /// of that region. Otherwise, it should be zero.
+            /// </summary>
+            public readonly int OwnSize;
+
+            /// <summary>
+            /// Data used to compute the hash for this entry.
+            /// </summary>
+            /// <remarks>
+            /// To avoid additional allocations, this might be a instance of the full entry data,
+            /// and only a sub-region of it might be actually used by this entry. Such sub-region
+            /// has its size indicated by <see cref="OwnSize"/> in this case.
+            /// </remarks>
+            public readonly byte[] Data;
+
+            /// <summary>
+            /// Item associated with this entry.
+            /// </summary>
+            public T Item;
+
+            /// <summary>
+            /// Indicates if the entry is partial, which means that this entry is only for a sub-region of the data.
+            /// </summary>
+            /// <remarks>
+            /// Partial entries have no items associated with them. They just indicates that the data might be present on
+            /// the table, and one must keep looking for the full entry on other tables of larger data size.
+            /// </remarks>
+            public bool IsPartial => OwnSize != 0;
+
+            /// <summary>
+            /// Creates a new partial hash table entry.
+            /// </summary>
+            /// <param name="hash">Hash of the data</param>
+            /// <param name="ownerData">Full data</param>
+            /// <param name="ownSize">Size of the sub-region of data that belongs to this entry</param>
+            public Entry(uint hash, byte[] ownerData, int ownSize)
+            {
+                Hash = hash;
+                OwnSize = ownSize;
+                Data = ownerData;
+                Item = default;
+            }
+
+            /// <summary>
+            /// Creates a new full hash table entry.
+            /// </summary>
+            /// <param name="hash">Hash of the data</param>
+            /// <param name="data">Data</param>
+            /// <param name="item">Item associated with this entry</param>
+            public Entry(uint hash, byte[] data, T item)
+            {
+                Hash = hash;
+                OwnSize = 0;
+                Data = data;
+                Item = item;
+            }
+
+            /// <summary>
+            /// Gets the data for this entry, either full or partial.
+            /// </summary>
+            /// <returns>Data sub-region</returns>
+            public ReadOnlySpan<byte> GetData()
+            {
+                if (OwnSize != 0)
+                {
+                    return new ReadOnlySpan<byte>(Data).Slice(0, OwnSize);
+                }
+
+                return Data;
+            }
+        }
+
+        /// <summary>
+        /// Hash table bucket.
+        /// </summary>
+        private struct Bucket
+        {
+            /// <summary>
+            /// Inline entry, to avoid allocations for the common single entry case.
+            /// </summary>
+            public Entry InlineEntry;
+
+            /// <summary>
+            /// List of additional entries for the not-so-common multiple entries case.
+            /// </summary>
+            public List<Entry> MoreEntries;
+        }
+
+        private Bucket[] _buckets;
+        private int _count;
+
+        /// <summary>
+        /// Total amount of entries on the hash table.
+        /// </summary>
+        public int Count => _count;
+
+        /// <summary>
+        /// Creates a new instance of the partitioned hash table.
+        /// </summary>
+        public PartitionHashTable()
+        {
+            _buckets = Array.Empty<Bucket>();
+        }
+
+        /// <summary>
+        /// Gets an item on the table, or adds a new one if not present.
+        /// </summary>
+        /// <param name="data">Data</param>
+        /// <param name="dataHash">Hash of the data</param>
+        /// <param name="item">Item to be added if not found</param>
+        /// <returns>Existing item if found, or <paramref name="item"/> if not found</returns>
+        public T GetOrAdd(byte[] data, uint dataHash, T item)
+        {
+            if (TryFindItem(dataHash, data, out T existingItem))
+            {
+                return existingItem;
+            }
+
+            Entry entry = new Entry(dataHash, data, item);
+
+            AddToBucket(dataHash, ref entry);
+
+            return item;
+        }
+
+        /// <summary>
+        /// Adds an item to the hash table.
+        /// </summary>
+        /// <param name="data">Data</param>
+        /// <param name="dataHash">Hash of the data</param>
+        /// <param name="item">Item to be added</param>
+        /// <returns>True if the item was added, false due to an item associated with the data already being on the table</returns>
+        public bool Add(byte[] data, uint dataHash, T item)
+        {
+            if (TryFindItem(dataHash, data, out _))
+            {
+                return false;
+            }
+
+            Entry entry = new Entry(dataHash, data, item);
+
+            AddToBucket(dataHash, ref entry);
+
+            return true;
+        }
+
+        /// <summary>
+        /// Adds a partial entry to the hash table.
+        /// </summary>
+        /// <param name="ownerData">Full data</param>
+        /// <param name="ownSize">Size of the sub-region of <paramref name="ownerData"/> used by the partial entry</param>
+        /// <returns>True if added, false otherwise</returns>
+        public bool AddPartial(byte[] ownerData, int ownSize)
+        {
+            ReadOnlySpan<byte> data = new ReadOnlySpan<byte>(ownerData).Slice(0, ownSize);
+
+            return AddPartial(ownerData, HashState.CalcHash(data), ownSize);
+        }
+
+        /// <summary>
+        /// Adds a partial entry to the hash table.
+        /// </summary>
+        /// <param name="ownerData">Full data</param>
+        /// <param name="dataHash">Hash of the data sub-region</param>
+        /// <param name="ownSize">Size of the sub-region of <paramref name="ownerData"/> used by the partial entry</param>
+        /// <returns>True if added, false otherwise</returns>
+        public bool AddPartial(byte[] ownerData, uint dataHash, int ownSize)
+        {
+            ReadOnlySpan<byte> data = new ReadOnlySpan<byte>(ownerData).Slice(0, ownSize);
+
+            if (TryFindItem(dataHash, data, out _))
+            {
+                return false;
+            }
+
+            Entry entry = new Entry(dataHash, ownerData, ownSize);
+
+            AddToBucket(dataHash, ref entry);
+
+            return true;
+        }
+
+        /// <summary>
+        /// Adds entry with a given hash to the table.
+        /// </summary>
+        /// <param name="dataHash">Hash of the entry</param>
+        /// <param name="entry">Entry</param>
+        private void AddToBucket(uint dataHash, ref Entry entry)
+        {
+            int pow2Count = GetPow2Count(++_count);
+            if (pow2Count != _buckets.Length)
+            {
+                Rebuild(pow2Count);
+            }
+
+            ref Bucket bucket = ref GetBucketForHash(dataHash);
+
+            AddToBucket(ref bucket, ref entry);
+        }
+
+        /// <summary>
+        /// Adds an entry to a bucket.
+        /// </summary>
+        /// <param name="bucket">Bucket to add the entry into</param>
+        /// <param name="entry">Entry to be added</param>
+        private void AddToBucket(ref Bucket bucket, ref Entry entry)
+        {
+            if (bucket.InlineEntry.Data == null)
+            {
+                bucket.InlineEntry = entry;
+            }
+            else
+            {
+                (bucket.MoreEntries ??= new List<Entry>()).Add(entry);
+            }
+        }
+
+        /// <summary>
+        /// Creates partial entries on a new hash table for all existing full entries.
+        /// </summary>
+        /// <remarks>
+        /// This should be called every time a new hash table is created, and there are hash
+        /// tables with data sizes that are higher than that of the new table.
+        /// This will then fill the new hash table with "partial" entries of full entries
+        /// on the hash tables with higher size.
+        /// </remarks>
+        /// <param name="newTable">New hash table</param>
+        /// <param name="newEntrySize">Size of the data on the new hash table</param>
+        public void FillPartials(PartitionHashTable<T> newTable, int newEntrySize)
+        {
+            for (int i = 0; i < _buckets.Length; i++)
+            {
+                ref Bucket bucket = ref _buckets[i];
+                ref Entry inlineEntry = ref bucket.InlineEntry;
+
+                if (inlineEntry.Data != null)
+                {
+                    if (!inlineEntry.IsPartial)
+                    {
+                        newTable.AddPartial(inlineEntry.Data, newEntrySize);
+                    }
+
+                    if (bucket.MoreEntries != null)
+                    {
+                        foreach (Entry entry in bucket.MoreEntries)
+                        {
+                            if (entry.IsPartial)
+                            {
+                                continue;
+                            }
+
+                            newTable.AddPartial(entry.Data, newEntrySize);
+                        }
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Tries to find an item on the table.
+        /// </summary>
+        /// <param name="dataHash">Hash of <paramref name="data"/></param>
+        /// <param name="data">Data to find</param>
+        /// <param name="item">Item associated with the data</param>
+        /// <returns>True if an item was found, false otherwise</returns>
+        private bool TryFindItem(uint dataHash, ReadOnlySpan<byte> data, out T item)
+        {
+            if (_count == 0)
+            {
+                item = default;
+                return false;
+            }
+
+            ref Bucket bucket = ref GetBucketForHash(dataHash);
+
+            if (bucket.InlineEntry.Data != null)
+            {
+                if (bucket.InlineEntry.Hash == dataHash && bucket.InlineEntry.GetData().SequenceEqual(data))
+                {
+                    item = bucket.InlineEntry.Item;
+                    return true;
+                }
+
+                if (bucket.MoreEntries != null)
+                {
+                    foreach (Entry entry in bucket.MoreEntries)
+                    {
+                        if (entry.Hash == dataHash && entry.GetData().SequenceEqual(data))
+                        {
+                            item = entry.Item;
+                            return true;
+                        }
+                    }
+                }
+            }
+
+            item = default;
+            return false;
+        }
+
+        /// <summary>
+        /// Indicates the result of a hash table lookup.
+        /// </summary>
+        public enum SearchResult
+        {
+            /// <summary>
+            /// No entry was found, the search must continue on hash tables of lower size.
+            /// </summary>
+            NotFound,
+
+            /// <summary>
+            /// A partial entry was found, the search must continue on hash tables of higher size.
+            /// </summary>
+            FoundPartial,
+
+            /// <summary>
+            /// A full entry was found, the search was concluded and the item can be retrieved.
+            /// </summary>
+            FoundFull
+        }
+
+        /// <summary>
+        /// Tries to find an item on the table.
+        /// </summary>
+        /// <param name="dataAccessor">Data accessor</param>
+        /// <param name="size">Size of the hash table data</param>
+        /// <param name="item">The item on the table, if found, otherwise unmodified</param>
+        /// <param name="data">The data on the table, if found, otherwise unmodified</param>
+        /// <returns>Table lookup result</returns>
+        public SearchResult TryFindItem(scoped ref SmartDataAccessor dataAccessor, int size, scoped ref T item, scoped ref byte[] data)
+        {
+            if (_count == 0)
+            {
+                return SearchResult.NotFound;
+            }
+
+            ReadOnlySpan<byte> dataSpan = dataAccessor.GetSpanAndHash(size, out uint dataHash);
+
+            if (dataSpan.Length != size)
+            {
+                return SearchResult.NotFound;
+            }
+
+            ref Bucket bucket = ref GetBucketForHash(dataHash);
+
+            if (bucket.InlineEntry.Data != null)
+            {
+                if (bucket.InlineEntry.Hash == dataHash && bucket.InlineEntry.GetData().SequenceEqual(dataSpan))
+                {
+                    item = bucket.InlineEntry.Item;
+                    data = bucket.InlineEntry.Data;
+                    return bucket.InlineEntry.IsPartial ? SearchResult.FoundPartial : SearchResult.FoundFull;
+                }
+
+                if (bucket.MoreEntries != null)
+                {
+                    foreach (Entry entry in bucket.MoreEntries)
+                    {
+                        if (entry.Hash == dataHash && entry.GetData().SequenceEqual(dataSpan))
+                        {
+                            item = entry.Item;
+                            data = entry.Data;
+                            return entry.IsPartial ? SearchResult.FoundPartial : SearchResult.FoundFull;
+                        }
+                    }
+                }
+            }
+
+            return SearchResult.NotFound;
+        }
+
+        /// <summary>
+        /// Rebuilds the table for a new count.
+        /// </summary>
+        /// <param name="newPow2Count">New power of two count of the table</param>
+        private void Rebuild(int newPow2Count)
+        {
+            Bucket[] newBuckets = new Bucket[newPow2Count];
+
+            uint mask = (uint)newPow2Count - 1;
+
+            for (int i = 0; i < _buckets.Length; i++)
+            {
+                ref Bucket bucket = ref _buckets[i];
+
+                if (bucket.InlineEntry.Data != null)
+                {
+                    AddToBucket(ref newBuckets[(int)(bucket.InlineEntry.Hash & mask)], ref bucket.InlineEntry);
+
+                    if (bucket.MoreEntries != null)
+                    {
+                        foreach (Entry entry in bucket.MoreEntries)
+                        {
+                            Entry entryCopy = entry;
+                            AddToBucket(ref newBuckets[(int)(entry.Hash & mask)], ref entryCopy);
+                        }
+                    }
+                }
+            }
+
+            _buckets = newBuckets;
+        }
+
+        /// <summary>
+        /// Gets the bucket for a given hash.
+        /// </summary>
+        /// <param name="hash">Data hash</param>
+        /// <returns>Bucket for the hash</returns>
+        private ref Bucket GetBucketForHash(uint hash)
+        {
+            int index = (int)(hash & (_buckets.Length - 1));
+
+            return ref _buckets[index];
+        }
+
+        /// <summary>
+        /// Gets a power of two count from a regular count.
+        /// </summary>
+        /// <param name="count">Count</param>
+        /// <returns>Power of two count</returns>
+        private static int GetPow2Count(int count)
+        {
+            // This returns the nearest power of two that is lower than count.
+            // This was done to optimize memory usage rather than performance.
+            return 1 << BitOperations.Log2((uint)count);
+        }
+    }
+}